Human spermatozoa have been found to violate Newton’s third law, according to a new study published in the journal PrX Life. The law states that “act is always equal to counteraction,” but it turns out that sperm distort their bodies while moving in a way that does not adhere to this principle.
Scientists conducted the study by analyzing the CHLAMYDOMONAS algae and data on human sperm. They discovered mechanical interactions, which they named the “strange elastic module,” that contradict Newton’s third law.
Both chlamydomonas and spermatozoa use hair outgrowths called flagella to aid in their movement. The flagella protrude from the cell and resemble a tail, allowing the cell to change shape and move by interacting with the surrounding liquid. However, this interaction is done asymmetrically, without producing an equal and opposite response from the environment, thereby violating Newton’s law.
In addition to the elasticity of the flagella, the “strange elastic module” plays a crucial role in the cell’s movement. This module enables cells to move their flagella without significant energy losses that would hinder their mobility.
The study found that cells with a higher “strange elastic module” are able to generate waves with the flagella more efficiently, without experiencing large energy losses, thus enabling better forward movement that contradicts traditional physics.
Flagella are not exclusive to sperm and algae. Many microorganisms also possess these outgrowths, suggesting the possible existence of other “violators” of Newton’s third law. The authors of the study believe that understanding and classifying cells or organisms that exhibit asymmetric movement can be highly advantageous.
Furthermore, the approach taken by scientists in this study could potentially aid in the development of small elastic robots that can violate Newton’s third law. Kent Isimoto, one of the study’s authors from the University of Kyoto in Japan, expressed its potential applications in creating such robots.
By shedding light on the behavior of human sperm and other microorganisms, this research provides valuable insights into the violation of Newton’s third law in the living world.
